1. Technical Field
The technical field relates to an interchangeable lens, a camera body, and a camera system, and particularly relates to a camera body which performs autofocus control in recording of moving image, an interchangeable lens compatible with the camera body, and a camera system having the camera body and the interchangeable lens.
2. Related Art
JP-A-4-280239 discloses a camera apparatus of interchangeable lens type having a camera unit and a lens unit detachably mountable to the camera unit. The lens unit has a drive system relating to automatic focus regulation and automatic exposure control. Further, the lens unit has status information about the lens unit. In this camera apparatus, various control information and the status information are communicated between the camera unit and the lens unit, so that the camera unit controls the lens unit.
In order to realize autofocus operation in recording of moving images, wobbling control is performed. In the wobbling control, while a focus lens is being advanced and retreated to an optically axial direction by a very short distance and a focus direction is being detected, the focus lens is moved to a direction of a focus position. Further, in a lens unit having a zoom lens and a focus lens, when the focus lens is moved with a focus state being maintained, accordingly the zoom lens occasionally moves. In such a lens unit, when the above wobbling control is performed, a field angle periodically fluctuates by small oscillation of the focus lens. As the zoom lens is closer to a wide-angle side, the fluctuation becomes more remarkable. Therefore, when the wobbling control is performed during recording of moving images, the field angle of the moving images recorded by the imaging device changes, and thus the images become ugly for users. In the conventional camera apparatuses of interchangeable lens type (for example, the camera apparatus of interchangeable lens type disclosed in the JP-A4-280239), when moving images are recorded, automatic focus regulation cannot suitably performed for every state of the zoom lens, and thus the above problems caused by the wobbling control cannot be solved.